Hollow bar in two pieces



Feb. 24, 1925. 1,527,728

H K.ARNSTHN v HOLLOW BAR IN TWO PIECES Filed June 28, 1920 INVENTOR= Patented'Feb. 24, 1925.

RICHSHAFEN, GERMANY.

1,527,728 PATENT "OFFICE.

KARL ARNSTEIN, OF FRIEDRICHSHAFEN, GEIMANY, ASSIGNOR TO THE FIRM LU'FT- SCHIFFBAU ZEIPPELIN (:rESELLSCI-IAIETv MIT IBESCHRANKTER I-IAFTUNG, OF FRIED- HOLLOW BAR In Two Pmions.

Application filed. me as, 1920. Serial No. 92,484.

(GRANTED UNDER THE PROVISIONS OF THE' ACT OF MARCH 3. 1921, 11 STAT. I, 1313.)

To all whom it may concern:

Be it known that I, KARL AnNs'rEIN, a citizen of the Czechoslovakian Republic, .re-

siding at Friedrichshafen, Germany, have invented certain new and useful Improvements in Hollow Bars in Two Pieces (for which I have filed application in Germany. Nov. 5th, 1917), of which the following is a specification.

My invention refers to hol-low liars such as used in light structures, e. g. in the construction of ar craft, which for this reason must combine a minimum weight with a maximum resistance to buckling and bending. My invention concerns especially a hollow bar made in two'pieces of such design-that it can easily be connected with other bars and chiefly comes into considerationfor the booms of light girders. It is especially suitable for compound joints and system points of light girders, e. g. of frames for airships of the rigid type.

The new hollow bar made in two piecesconsists "of a hollow part having a section with three or more faces-and; connection flanges pointing in the direction of the ad= joining frame-work members and a U- shaped cover strip with obtuse-angled flanges of the same inclination. Preferabl'y. the faces of the hollow part of the section opposite the cover strip are arranged fairly in parallel to the flanges intended to connect it with the cover str'p. On account of'the particular shape of the section lateral bars can be easily joined and the joint is permanently easily accessible for work to be done, so that it can be reinforced without any trouble, no'matter whether one or several lateral bare are to be joined or not. The joint is reinforced according to the invention by covering the hollow part of the section by an inner butt and an outer connecting plateafter'thecover strip has been cut out to match. Upon the missing stretch'a connection plate is riveted, which, like the connection plate already mounted, is fitted on both sides with overlapping ends for the adjoining of the lattice work bars. The hollow. part of the section can possess three, four or five faces, so that the finished section has tour, five or six sides. A hollow bar of pentagonal section has proved especially advantageous as having a great replate with one bend only can be used for the connection with lateral bars. With fourand six-sided sections such a connection plate has two bends. On the other hand w th the four-sided section, especially if its adjoining faces are made perpendicular to one another, the inner butt serving tocover the-joint has the simplest section. The six-sided sectionagain offers the advan-' tags that adjoining bars of thesame height of section have the smallest height. the sides next to the adjo'ning bars ,are' arranged approximately perpendicular upon the sides next to the top of the section, the

vsistance to shocks and because a connection lattice work barsean be cut oil at-f'ight an- I gles to their longitudinal axis, whereby the connection is made simpler and the connection plates are enlarged. In the drawings aliixed to this specification and forming part thereofgseveralmod- In the examples shown in Figs. 15 the primary shape of the polygonal'sec-tion A is either a quadrangle or a penta on or a hexagon. The comparatively wi e cover strip B has flanges b which are bent more or less outwards. In Fig. 1 the outer walla stands upright upon the .side walls a between them and the connection flanges a. In Fig. 2 each flange b is bent sideways, in Figs. 3, 5, 6 and 9 each flange is parallel to side a of-the hollow part A of the section adjacent to the flanged side a In Figs. 1v and 2 the connection flanges a are arranged obliquely on the adjacent sides a In Fig. 3 the angle of 'inclinationbetween theflanges a and sides a is approximately and in Figs. 4 and 5 exactly In the assembled joint according to Figs.

" be a closed hollow square.

enough as to be riveted on to the 6-9 two main booms An meet in one centre with two lateral bars C arranged perpendicularly upon them. In the jointed ends of the main booms A, A both cover strips B are cut away far enough to be able 'flanges a of this section another outer connection'plateF is fastened by rivets. A somewhat longer cover strip G finally ensures a further reinforcement and a special joint cover of the cover strip section B, but is not indispensable. The lateral bars C, which may be of any section, are joined on individually according to their shape. In the example the section is supposed to In this case a connection without cutting into the bars is very easily made by riveting two U-bars 0 on to the ends of the bars and connecting their flanges with the plates E and F. In

a similar way any other open or closed section may used, as the plates E and F are easily accessible from all sides.

. By varying the angle at the apex of the pentagon one may obtain as well assembling points fora three or four-edged pyramidal 1.. A structural sheet metal member com prising in combination, a flanged polygonal channel member and a flat plate or strip applied against and fixed to the flanges of said member so as to cover the channel, sald flanges and the parts of said plate or strip contacting therewith extending at air-obtuse angle to said plate or strip.

2. A structural sheet metal member coniprising in combination, a flanged pentagonal channel member and a flat plate or strip applied against and fixed to the flanges of said member so as to cover the channel, said flanges and the parts of said plate or'strip contacting therewith extending at an obtuse angle to said plate or strip, and in parallel with the bottom portion of said channel disposed on the same side.

In testimony whereof I affix my signature.

KARL ARNSTEIN. 

